The effects of test order and nodal distance on the emergence and stability of derived discriminative stimulus functions

The present study examined the effects of equivalence test order and nodal distance on the emergence and stability of derived discriminative stimulus functions. Participants in 1 group were exposed to a transfer of functions test following a symmetry and equivalence test, another group of participants completed a symmetry and equivalence test follovwing a transfer test, and a final group of participants received a symmetry test only if they failed to demonstrate immediate transfer, after which time they were retested. At least 1 month following their initial laboratory experience, all participants who had demonstrated the transfer of functions were contacted and asked to return to the laboratory for a follow-up transfer test. Results showed that a prior equivalence test was not necessary for the transfer of functions, although a symmetry test may have facilitated transfer for some participants, A nodal distance effect for the stability of the derived stimulus functions was observed during the follow-up transfer test.